A voltage inverter is commonly used to power the backlight in a variety of display devices, such as a liquid crystal display (LCD). In an LCD, a backlight illuminates the back side of an array of thin-film transistors. Each of the transistors in the thin-film array acts like a tiny shutter that can open or close to pass more or less light from the backlight. Each transistor may represent one tiny dot on an LCD, and an LCD may include hundreds of thousand, or even millions, of these tiny dots. By individually controlling the amount of light passed by each transistor, an image can be displayed on an LCD.
A backlight often uses a relatively high voltage, alternating current (AC) power source. Many devices, however, primarily use comparatively low voltage, direct current (DC) power sources. For instance, a typical laptop computer may provide 3.3 volts DC to power its display. A typical backlight, such as a cold cathode florescent lamp (CCFL), may require 2000 volts root mean square (rms), which is an AC signal.
A voltage inverter is commonly used in displays because a voltage inverter can convert small DC voltage, such as a battery DC, to large AC voltage, such as 2000 volts rms. A voltage inverter, however, can consume a relatively large amount of power in many devices. High power consumption can be undesirable, especially in mobile devices like laptop computers.